nodejs async how to set callback - node.js

Question

I have the following piece of code which is working fine.
var config = require('./config');
var cheerio = require('cheerio');
var myhttp = require('./myHttp');
var stringHelper = require('./stringHelper');
var Base64 = require('./base64.js').Base64;
var Encrypt = require('./Encrypt.js');
var myEncode = require('./Encode.js');
var rules = require('./rules');
var io = require('socket.io-emitter')({ host: '127.0.0.1', port: 6379 });
var mysql = require('mysql');
delete require.cache[require.resolve('./requestLogin1.js')]
var myvar = require('./requestLogin1.js');
var connection = mysql.createConnection(
{
host : 'localhost',
user : 'root',
password : 'abc',
database : 'abcd'
}
);
connection.connect(function(err) {
if (err) {
console.log('error connecting: ' + err.stack);
return;
}
});
var timerOB;
var timerMW;
var timerP;
var timerTL;
var news = {
'mw': [],
'ob': [],
'all': {},
};
var status = false;
function round(rnum, rlength) {
return newnumber = Math.round(rnum * Math.pow(10, rlength)) / Math.pow(10, rlength);
}
function roundup(rnum, rlength) {
return newnumber = Math.ceil(rnum * Math.pow(10, rlength)) / Math.pow(10, rlength);
}
function rounddown(rnum, rlength) {
return newnumber = Math.floor(rnum * Math.pow(10, rlength)) / Math.pow(10, rlength);
}
function function1(_html) {
console.log('function1 run')
var $ = cheerio.load(_html);
var v_lgnid = $('#userId').attr('value');
var v_psswrd = config.password;
var v_data = v_lgnid + "|" + v_psswrd;
var _key = $('#accntid').attr('value');
if (_key) {
v_data = Base64.encode(Encrypt.AESEncryptCtr(v_data, _key , "256"));
v_data = escape(v_data);
myhttp.get(
'https://example.com/ValidPassword.jsp?' + $('#name').attr('value') + "=" + v_data,
function (_htmlShowImage) {
if (_htmlShowImage && _htmlShowImage.trim() == "OK") {
function2();
} else {
console.log('Login Fail');
}
});
} else {
login();
console.log('Encrypt password error');
}
}
function function2() {
myhttp.get(
'https://example.com/QuestionsAuth.jsp',
function (_htmlShowImage) {
var $ = cheerio.load(_htmlShowImage);
var sLoginID = $('#sLoginID').attr('value');
var Answer1 = config.answer1;
var Answer2 = config.answer2;
var Index1 = $('#st1').attr('value');
var Index2 = $('#st2').attr('value');
var v_data = sLoginID + "|" + Answer1 + "|" + Answer2 + "|" + Index1 + "|" + Index2;
v_data = Base64.encode(Encrypt.AESEncryptCtr(v_data, $('#key_questauth').attr('value'), "256"));
v_data = escape(v_data);
myhttp.get(
'https://example.com/ValidAnswers.jsp?' + $('#name_questauth').attr('value') + "=" + v_data,
function (_htmlShowImage) {
if (_htmlShowImage && _htmlShowImage.trim() == "OK") {
//rootCallback();
myhttp.get(
'https://example.com/DefaultLogin.jsp',
function (_html) {
console.log('Login sucess')
stringHelper.SaveFileCookies('abcd.txt', myhttp.loadCookie(), 'save cookie login sucess');
if (timerMW) {
clearTimeout(timerMW);
}
timerMW = setTimeout(function6, config.DelayExtractMW);
if (timerOB) {
clearTimeout(timerOB);
}
timerOB = setTimeout(function5, config.DelayExtractOB);
if (timerP) {
clearTimeout(timerP);
}
timerP = setTimeout(function4, config.function4);
});
} else {
console.log('Login Fail - timer');
}
});
});
}
var login = function () {
if (timerMW) {
clearTimeout(timerMW);
}
if (timerOB) {
clearTimeout(timerOB);
}
if (timerP) {
clearTimeout(timerP);
}
if (timerTL) {
clearTimeout(timerTL);
}
myhttp.init();
myhttp.post(
'https://example.com/ShowImage.jsp',
{ "requiredLogin": myEncode.Convert(config.uname) },
function (_htmlpost) {
if (_htmlpost) {
function1(_htmlpost);
} else {
if (timerTL) {
clearTimeout(timerTL);
}
timerTL = setTimeout(login, config.DelayNestError);
}
});
}
exports.login = login;
function function3() {
return {
TS: '',
MWP: 0,
LTP: 0,
NQ: 0,
OBBP: '',
OBSP: '',
CurrTime: 0,
rules: {}
};
}
function function4() {
status = false;
myhttp.get('https://example.com/PB.jsp?Exchange=',
function (_html) {
if (_html && _html.length > 10) {
news.pn = {};
$ = cheerio.load(_html);
$('tr[id^="TR"]').each(function () {
status = true;
var symbol = $('td:nth-child(3)', this).text().trim();
var objob = {
'NQ': parseInt($('td:nth-child(11)', this).text().trim()),
};
var post = {
'symbol': symbol,
'nq': objob.NQ
};
connection.query('INSERT INTO NP SET ?', post, function (err,result){
if (err)
{console.log("NP sql insert error : " +symbol);}
else {
console.log("data inserted into NP Table : " +symbol);
}
});
var objstock = news.all[symbol];
if (typeof objstock!='undefined') {
objstock.NQ = objob.NQ;
news.pn[symbol] = objob;
news.all[symbol] = objstock;
if (status) {
io.emit('news', news);
}
}
else
{
console.log('symbol not found');
}
});
if (timerP) {
clearTimeout(timerP);
}
console.log('setTimer function4:' + config.DelayExtractPn);
timerP = setTimeout(function4, config.DelayExtractPn);
}
connection.query('UPDATE MASTER1 SET tbq = (SELECT sum(a.bq) FROM (select distinct symbol, bq from NP) as a)', function (err,result){
if (err)
{console.log("CQ06 skipped: ");}
else {
console.log("Step 6 - Master1 tbq data updated");
}
});
connection.query('UPDATE MASTER1 SET tsq = (SELECT sum(a.sq) FROM (select distinct symbol, sq from NP) as a)', function (err,result){
if (err)
{console.log("CQ07 skipped: ");}
else {
console.log("Step 7 - Master1 tsq data updated");
}
});
});
}
function function5() {
status = false;
myhttp.get('https://example.com/OB.jsp?Exchange=&OrderType=All',
function (_html) {
if (_html && _html.length > 10) {
$ = cheerio.load(_html);
console.log('OB - Step 2 - html loaded for parsing');
news.ob = [];
$('tr[id^="TR"]').each(function () {
var statusOrder = $('td:nth-child(20)', this).text().trim();
if (statusOrder.toLowerCase().indexOf('open') >= 0) {
status = true;
var objob = {
'symbol': $('td:nth-child(6)', this).text().trim(),
'buysell': $('td:nth-child(9)', this).text().trim(),
'ordernumber': $('input[name="Select"]', this).attr('value'),
};
var objstock = news.all[objob.symbol];
objstock.OBBP = objob.buysell == "BUY"?objob.ordernumber:"";
objstock.OBSP = objob.buysell == "SELL"?objob.ordernumber:"";
news.ob.push(objob);
}
});
if (status) {
io.emit('news', news);
}
if (timerOB) {
clearTimeout(timerOB);
}
timerOB = setTimeout(function5, config.DelayExtractOB);
}
});
}
function function6() {
myhttp.get(
'https://example.com/MW.jsp?',
function (_html) {
if (_html && _html.length > 10) {
var $ = cheerio.load(_html);
status = false;
news.mw = [];
var countCheckRule = 0;
var countCheckedRule = 0;
var tmpall = {};
$('tr[onclick]').each(function () {
status = true;
var data1 = $("input[onclick*='Apply(']", this).attr('onclick');
var arrdata1 = data1.split("','");
var stockid = arrdata1[1].split('|')[0];
var symbol = $('td:nth-child(3)', this).text().trim();
var price = parseFloat($('td:nth-child(4)', this).text().trim());
var cTime = stringHelper.getIndiaTime();
var CurrTime = cTime.toLocaleTimeString();//(will be updated every 60 seconds)
news.mw.push({
'symbol': symbol,
'price': price,
'stockid': stockid,
'CurrTime': CurrTime,
});
var objstock = news.all[symbol];
if (!objstock) {
objstock = function3();
}
if (!news.pn[symbol]) {
objstock.NQ = 0;
}
var notfoundob = true;
for (var symbolkey in news.ob) {
if (news.ob[symbolkey].symbol == symbol) {
notfoundob = false;
}
}
if (notfoundob) {
objstock.OBBP = "";
objstock.OBSP = "";
}
objstock.TS = symbol;//trade symbol
objstock.MWP = stockid;//trade id
objstock.LTP = price;
objstock.CurrTime = CurrTime;
rules.checRules(objstock, myhttp, function (rules_res) {
objstock.rules = rules_res;
tmpall[symbol] = objstock;
});
countCheckRule++;
});
rules.rule12(tmpall, function (_tmpall) {
tmpall = _tmpall;
});
news.all = tmpall;
if (!status) {
login();
console.log('MW - Step 9 - logged out');
} else {
io.emit('news', news);
if (timerMW) {
clearTimeout(timerMW);
}
timerMW = setTimeout(function6, config.DelayExtractMW);
}
} else {
if (timerMW) {
clearTimeout(timerMW);
}
timerMW = setTimeout(function6, config.DelayExtractMW);
}
});
}
Now i want to use async to ensure that function6 is run only after function4 & function5 is run.
I have tried to learn about async from various forums and have changed the code as follows:
var async = require('async'); //line added
// change made
async.parallel([
function function4(callback) {
status = false;
myhttp.get('https://example.com/PB.jsp?Exchange=',
function (_html) {
if (_html && _html.length > 10) {
news.pn = {};
$ = cheerio.load(_html);
$('tr[id^="TR"]').each(function () {
status = true;
var symbol = $('td:nth-child(3)', this).text().trim();
var objob = {
'NQ': parseInt($('td:nth-child(11)', this).text().trim()),
};
console.log('Posn - Step 3A - Found position:' + symbol);
var post = {
'symbol': symbol,
'nq': objob.NQ
};
connection.query('INSERT INTO NP SET ?', post, function (err,result){
if (err)
{console.log("NP sql insert error : " +symbol);}
else {
console.log("data inserted into NP Table : " +symbol);
}
});
var objstock = news.all[symbol];
if (typeof objstock!='undefined') {
objstock.NQ = objob.NQ;
news.pn[symbol] = objob;
news.all[symbol] = objstock;
if (status) {
io.emit('news', news);
}
}
else
{
console.log('symbol not found');
}
});
if (timerP) {
clearTimeout(timerP);
}
console.log('setTimer function4:' + config.DelayExtractPn);
timerP = setTimeout(function4, config.DelayExtractPn);
}
connection.query('UPDATE MASTER1 SET tbq = (SELECT sum(a.bq) FROM (select distinct symbol, bq from NP) as a)', function (err,result){
if (err)
{console.log("CQ06 skipped: ");}
else {
console.log("Step 6 - Master1 tbq data updated");
}
});
connection.query('UPDATE MASTER1 SET tsq = (SELECT sum(a.sq) FROM (select distinct symbol, sq from NP) as a)', function (err,result){
if (err)
{console.log("CQ07 skipped: ");}
else {
console.log("Step 7 - Master1 tsq data updated");
}
});
callback(); //line added
});
},
function function5(callback) {
status = false;
myhttp.get('https://example.com/OB.jsp?Exchange=&OrderType=All',
function (_html) {
if (_html && _html.length > 10) {
$ = cheerio.load(_html);
console.log('OB - Step 2 - html loaded for parsing');
news.ob = [];
$('tr[id^="TR"]').each(function () {
var statusOrder = $('td:nth-child(20)', this).text().trim();
if (statusOrder.toLowerCase().indexOf('open') >= 0 || statusOrder.toLowerCase().indexOf('trigger pending') >= 0) {
status = true;
var objob = {
'symbol': $('td:nth-child(6)', this).text().trim(),
'buysell': $('td:nth-child(9)', this).text().trim(),
'ordernumber': $('input[name="Select"]', this).attr('value'),
};
var objstock = news.all[objob.symbol];
objstock.OBBP = objob.buysell == "BUY"?objob.ordernumber:"";
objstock.OBSP = objob.buysell == "SELL"?objob.ordernumber:"";
news.ob.push(objob);
}
});
if (status) {
console.log('OB - Step 5 - pushed to html page');
io.emit('news', news);
}
if (timerOB) {
clearTimeout(timerOB);
}
timerOB = setTimeout(function5, config.DelayExtractOB);
}
callback(); //line added
});
}
],
function function6() {
myhttp.get(
'https://example.com/MW.jsp?',
function (_html) {
if (_html && _html.length > 10) {
var $ = cheerio.load(_html);
status = false;
news.mw = [];
var countCheckRule = 0;
var countCheckedRule = 0;
var tmpall = {};
$('tr[onclick]').each(function () {
status = true;
var data1 = $("input[onclick*='Apply(']", this).attr('onclick');
var arrdata1 = data1.split("','");
var stockid = arrdata1[1].split('|')[0];
var symbol = $('td:nth-child(3)', this).text().trim();
var price = parseFloat($('td:nth-child(4)', this).text().trim());
var cTime = stringHelper.getIndiaTime();
var CurrTime = cTime.toLocaleTimeString();//(will be updated every 60 seconds)
news.mw.push({
'symbol': symbol,
'price': price,
'stockid': stockid,
'CurrTime': CurrTime,
});
var objstock = news.all[symbol];
if (!objstock) {
objstock = function3();
}
if (!news.pn[symbol]) {
objstock.NQ = 0;
}
var notfoundob = true;
for (var symbolkey in news.ob) {
if (news.ob[symbolkey].symbol == symbol) {
notfoundob = false;
}
}
if (notfoundob) {
objstock.OBBP = "";
objstock.OBSP = "";
}
objstock.TS = symbol;//trade symbol
objstock.MWP = stockid;//trade id
objstock.LTP = price;
objstock.CurrTime = CurrTime;
rules.checRules(objstock, myhttp, function (rules_res) {
objstock.rules = rules_res;
tmpall[symbol] = objstock;
});
countCheckRule++;
});
//new check rules
rules.rule12(tmpall, function (_tmpall) {
tmpall = _tmpall;
});
news.all = tmpall;
if (!status) {
login();
} else {
io.emit('news', news);
if (timerMW) {
clearTimeout(timerMW);
}
timerMW = setTimeout(function6, config.DelayExtractMW);
}
} else {
if (timerMW) {
clearTimeout(timerMW);
}
timerMW = setTimeout(function6, config.DelayExtractMW);
}
});
});
Since my original functions do not have any callback, and since async needs callback, i have tried to code a callback in function4 & function5 - but I guess i have not coded it correctly.
I am getting an error in the line where callback is present that states "TypeError: undefined is not a function".
How do i correct this?
Related Question No. 2 : the current code has a timer function whereby function4, function5 and function6 runs with a preset timer. If async works, how do i define a timer whereby the combined set of function4,5 & 6 works based on a preset timer?
Sorry about the long code -- i am new to nodejs and was handed over this code as such and am trying to get this change made.
Thanks for your guidance.

Answer 1

You can instead make function4 and function5 to return promise and then execute function6 only after both function4's and function5's promise gets resolved.